you can not unless you trade
if you go to your home town you can fight the trainer at your friends house once you beat the game
you cant but in soulsilver you trade it with an upgrade
yes. porygon2 is a strong Pokemon
Porygon2 is a Normal type pokemon.
Porygon2 is a 2nd gen pokemon and does not appear in Pokemon Red. That aside, both of Porygon's evolutions occur when you trade it while it holds certain item. Up-Grade for Porygon to Porygon2, and Dubious Disc for Porygon2 to Porygon-Z.
It is impossible to obtain a Porygon2 without trading. You can get a Porygon and trade it with an Up-Grade or you can get a Porygon2 from the GTS but there is no way to get Porygon2 without trading.
Porygon2 is #233 in the national pokedex, and it is a Normal type Pokemon.
porygon2
You evolve Porygon2 by giving it the Dubious Disc and then trading it to another player's game.
You have to trade with it holding the dubious disk. This can be done when porygon2 is at any level.
It evolves Porygon to Porygon2 through trade.Dubious disc will then change Porygon2 to PorygonZ
porygon2